Re: [PATCH] ibmvnic: Use -EBUSY in __ibmvnic_reset()

[Nick Child]

On 4/23/24 06:55, Dan Carpenter wrote:
> On Tue, Apr 23, 2024 at 12:54:55PM +0200, Paolo Abeni wrote:
> > On Fri, 2024-04-19 at 16:08 +0200, Markus Elfring wrote:
> > > From: Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx>
> > > Date: Fri, 19 Apr 2024 15:46:17 +0200
> > >
> > > Add a minus sign before the error code “EBUSY”
> > > so that a negative value will be used as in other cases.
> > >
> > > This issue was transformed by using the Coccinelle software.
> > >
> > > Signed-off-by: Markus Elfring <elfring@xxxxxxxxxxxxxxxxxxxxx>
> > > ---
> > >   drivers/net/ethernet/ibm/ibmvnic.c | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
> > > index 5e9a93bdb518..737ae83a836a 100644
> > > --- a/drivers/net/ethernet/ibm/ibmvnic.c
> > > +++ b/drivers/net/ethernet/ibm/ibmvnic.c
> > > @@ -3212,7 +3212,7 @@ static void __ibmvnic_reset(struct work_struct *work)
> > >   		    adapter->state == VNIC_REMOVED) {
> > >   			spin_unlock_irqrestore(&adapter->state_lock, flags);
> > >   			kfree(rwi);
> > > -			rc = EBUSY;
> > > +			rc = -EBUSY;
> > >   			break;
> >
> > AFAICS the error is always used as bool, so this will not change any
> > behavior in practice. I tend to think we should not merge this kind of
> > change outside some larger work in the same area, but I'd love a second
> > opinion from the driver owners.
>
> I missed the original patch due to my procmail filters...
>
> You're right that it doesn't affect the behavior of the driver except
> for the debug output when we do:
>
> 	netdev_dbg(adapter->netdev, "Reset failed, rc=%d\n", rc);
>
> But the - was left off uninitentionally so I think we should apply it.
>
> I have been trying to look for similar bugs where the - is left off.
> It's a bit challenging because there places where we use positive
> error codes deliberately.  But in this case a static checker could
> easily detect the bug with a low false positive ratio by saying, "We're
> mixing normal negative error codes with positive EBUSY".
>
> regards,
> dan carpenter

Hello, small clarification, this patch will not effect the debug print 
statement due to the break statement immediately following:
	while () {	
		if () {
			rc = -EBUSY;
			break;
		}
		netdev_dbg(adapter->netdev, "Reset failed, rc=%d\n", rc);
	}
Though this return code can be passed to adapter->reset_done_rc, which 
is only treated as a boolean.

So, the point of the patch not doing any behavioral differences is still 
true.
Personally, I don't have strong opinions on this.
Reviewed-by: Nick Child <nnac123@xxxxxxxxxxxxx>